*{
				margin: 0;
				padding: 0;
			}
			#wrap{
				position: relative;
				width: 300px;
				height: 400px;
				border: 1px solid;
				margin: 0 auto;
				.inner{
					position: absolute;
					left: 0;
					right: 0;
					bottom: 0;
					top: 0;
					margin: auto;
					
					background: blue;
					width:100px;
					height: 100px;
				}
			}